// Copyright (C) Kumo inc. and its affiliates.
// Author: Jeff.li lijippy@163.com
// All rights reserved.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
//

package checkpoint

import (
	"reflect"

	"github.com/kumose/kmopt/pkg/set"
)

// FieldSet is an ordered set stores fields and comparators, it's []CheckField
type FieldSet struct {
	set.AnySet
}

// Slice returns CheckField slice for iteration
func (fs *FieldSet) Slice() []CheckField {
	slice := []CheckField{}
	for _, f := range fs.AnySet.Slice() {
		slice = append(slice, f.(CheckField))
	}
	return slice
}

// CheckField is a field that should be checked
type CheckField struct {
	field string
	eq    func(any, any) bool
}

// Field returns new CheckField
func Field(name string, eq func(any, any) bool) CheckField {
	return CheckField{name, eq}
}

// Register register FieldSet to global for latter comparing
// If there are two fields with the same name, the first one will
// be used
func Register(fields ...CheckField) FieldSet {
	s := set.NewAnySet(func(a, b any) bool {
		return a.(CheckField).field == b.(CheckField).field
	})

	fields = append(fields, Field(hashKey, reflect.DeepEqual), Field(funcKey, reflect.DeepEqual))
	for _, f := range fields {
		s.Insert(f)
	}

	return FieldSet{*s}
}
